生物固氮肥是利用固氮微生物将空气中的氮元素固定在土壤中，产生代谢产物，供作物生长所需。为了解这类肥料的肥效，作者近年在大白菜上进行了试验，现将结果简报如下。１材料与方法１．１供试肥源天丰牌生物固氮肥（北戴河产）。１.２试验方法试验于１９９７年４～６月在温州 Biological nitrogen fixation is the use of nitrogen fixation microorganisms in the air of nitrogen fixed in the soil, produce metabolites, for crop growth. In order to understand the effectiveness of such fertilizers, the author conducted experiments on Chinese cabbage in recent years, the results of which are summarized as follows. 1 Materials and Methods 1.1 Test Fertilizer Tianfeng card biological nitrogen fertilizer (Beidaihe production). 1.2 Test Method The test in April 4 ~ June 1997 in Wenzhou